From b35e5e29aa12090309e260e9966afb72beea5f55 Mon Sep 17 00:00:00 2001
From: Howard Hinnant <hhinnant@apple.com>
Date: Fri, 1 Apr 2011 00:54:26 +0000
Subject: [PATCH] made better error message for <atomic>

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/tags/libcpp-16@128699 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/atomic | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/atomic b/include/atomic
index daf64b26..31385a23 100644
--- a/include/atomic
+++ b/include/atomic
@@ -530,6 +530,10 @@ void atomic_signal_fence(memory_order m);
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+#if !__has_feature(cxx_atomic)
+#error <atomic> is not implemented
+#else
+
 typedef enum memory_order
 {
     memory_order_relaxed, memory_order_consume, memory_order_acquire,
@@ -1502,6 +1506,8 @@ typedef atomic<uintmax_t> atomic_uintmax_t;
 #define ATOMIC_LONG_LOCK_FREE 0
 #define ATOMIC_LLONG_LOCK_FREE 0
 
+#endif  //  !__has_feature(cxx_atomic)
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP_ATOMIC